Now that the iron filings have settled on Metallica's new album, let's look at a recent comment that Lars Ulrich made in a Guardian interview. The modest Dane claimed, "[E]veryone expects us to continue to release albums that define the genre, to 'save' metal." Eh? This begs at least two questions: Does metal need saving? And, if so, does anyone really expect a bunch of rich, middle-aged, hug-therapy addicts to do the saving?

I find it hard to believe that Metallica are still the standard bearers for metal. As a lapsed metaller, it sounds to me as if Lars is talking about a heavy metal world frozen in 1991, when Metallica were basking in the commercial success of their eponymous album (the "black album"). So for advice, I turned to Chris Chantler, writer for extreme music magazine Terrorizer, who points out that metal has always been respectful of its past. And he's right. In the 80s we listened to Judas Priest, Deep Purple and Black Sabbath, bands that flourished in the previous decade. However, Chantler goes further. "People look back because these bands have never been bettered – Sabbath, Priest, Iron Maiden, Motörhead and Metallica are cornerstones." It's a shameful reflection on today's metal, but perhaps he's right. Ask one of my pupils to name a metal band and they're more likely to say Iron Maiden than anyone who formed in the past two decades. Why is Guitar Hero littered with 70s and 80s metal gems? Well, let's start by looking at what makes a classic metal anthem.

It don't mean a thing if it ain't got that swingIf you listen to a forgotten Motörhead classic like Shine, or Black Sabbath's Hole in the Sky, you can hear a link back to 50s rock'n'roll and 60s psychedelic rock. You can tell that Lemmy and Ozzy's heroes are Little Richard and John Lennon. The swing is there in the bluesy bent notes, rather than precision-cut quaver riffing. Metallica are as guilty as anyone of introducing this lack of feel to metal; hear them mangle the groove out of Mercyful Fate's riffs. The best thrash metal, like Slayer and Anthrax, added a bit of groove to their moves, opening the way for Queens of the Stone Age and their stoner-rock precursors. But Metallica's linear chug, straitjacketed by the least funky drummer in history, only seems to have laid the foundations for humourless nonsense like Bullet for My Valentine.

SpaceEveryone learns how to play it, everyone says they are influenced by it, but NO ONE pays attention to AC/DC's judicious use of space in Back in Black. I've banged on about it before but really – when you're plumbing the metal depths you've got to come up for air occasionally.

BassDon't forget what this is for. Whether you're going to thrash chords out of it, like Lemmy loves to do, roll out galloping triplets as Iron Maiden's Steve Harris does, or deepen the riff like Sabbath-botherers Trouble or Cathedral, metal's not heavy without the low end weighing it down. Once again, Metallica are guilty. After gifted bass player Cliff Burton's untimely demise, Metallica might as well have not bothered replacing him for all the prominence they gave his substitute, poor old Jason Newsted. Legend has it that on …And Justice for All the newbie played identical bass parts to complement the guitar riffs, only to find that these were mixed so low on the final product that the bass lines are indistinguishable from the guitars - apart from a bizarrely bulging buzz where the frequencies of the instruments clash.

Performance over productionThe metal bands of the 70s and 80s had to rely on passion, conviction and eccentricity to play the fast, aggressive music they were pioneering. As Chantler points out, "Metal is about transgression and with studio software nowadays it is too easy to be fast." Napalm Death were revered in the 80s for their extremity, but now any band can be brutally fast and mastered loud to the point of distortion (which is why many reviewers have criticised Death Magnetic). Without this struggle, the clear idiosyncrasies of the great metal bands merge into a uniform heavy metal alloy.

Now I'm sure that heavy metal is still thriving in the margins, but as far as my ears can tell, these days there is no Ace of Spades or Enter Sandman set to become an air-guitar classic. But, if you think I've missed it, please correct me and nominate this generation's metal anthem.